Answer:
15 mph
Explanation:
Velocity = Distance/time
Distance, D = velocity * time
After 2 hours, the first train would have covered a distance of:
D1 = 60 * 2 = 120 miles
The second train would have covered a distance of:
D2 = 45 * 2 = 90
The difference in the distance covered by the two trains after 2 hours is:
ΔD = D1 - D2
ΔD = 120 -90
ΔD = 30 miles
The rate at which the distance is changing, Rate = ΔD/Δt
Rate = 30/2
Rate = 15 mph
